[Update: 08.22.2010] Valve has reportedly told PC Gamer that "The Sacrifice" will launch on October 5. The PC and Mac version will launch for free while the Xbox 360 version will cost 560MS Points ($7). According to PC Gamer, the Mac version will launch on October 5. Shacknews has contacted Valve to confirm the Xbox 360 version of the DLC will release alongside the PC and Mac.

[Original: 08.21.2010] Last night on GameTrailers TV, Valve's Chet Faliszek revealed info on upcoming downloadable content for those still waging war on the zombie threat. Read more »

With a dozen Left 4 Dead 2 "Mutations" released in as many weeks, Valve has collected a detailed breakdown of the modes developed to tweak the zombie-infested title's gameplay.

According to Valve, the most popular Mutation has been Realism Versus. The mode, which is now a permanent fixture in the game, captured the attention of 41% of all players the week it was initially released, making up for 22% of the each player's minutes when it launched. As a comparison, Survival Versus was only played by 25% of players for a total of 4% of their time with the game the week it was released. Read more »

Today is the last day in the, "Please! My wallet is begging you to stop" sale on Steam (otherwise known as the Perils of Summer sale).As expected, the final leg of the promotion rehash some of the best deals seen throughout the week. Highlights include Borderlands for $10.19 Left 4 Dead 2 for $10.16 and ARMA II for $19.99.

Steam Sale - July 4, 2010
• Just Cause 2 - $24.99 (50% off from $49.99) Read more »

The Left 4 Dead 2 mutation for owners of "The Passing" DLC for the next week is "Headshot!". In this mode, only headshots and decapitations will drop enemy zombies.

"Shoot them in the arm, shoot them in the leg, shoot them in the chest - it just doesn't matter! The only way these zombies are going down is with a head shot. Other hits will stumble them back, but only a head shot or decapitation will kill them." This mutation is available for the campaign. Read more »

Prima, longtime provider of video game strategy guides, will now be offering digital guides through Steam. Using the Steam overlay, guides can also be accessed within a game. The digital guides also include videos, which are obviously not available in print.

Regularly priced at $19.99, all guides are 50% off to celebrate the launch. Currently, guides are available for: Read more »

Our "Show Us Your Left 4 Dead Art Contest and Giveaway" has come to a close--the votes tallied, the commenters randomly chosen--and now it's time to announce the winners.

Simply narrowing the one hundred twenty eight images we received--located here and here--into twenty finalists was a tough task. The votes submitted by our panel of judged reflected how difficult it was to pick the five winners out of those twenty finalists--in fact, we had to call in additional "tie-breaker" judge. Read more »

The next mutation for Left 4 Dead 2 has gone into effect and will last until next Friday. This week, players can play "Last Gnome On Earth", which is playable in campaign mode. It requires the gnome to be carried from start to finish in order to win.

Be careful, though. Whoever is carrying the gnome will be swarmed by common infected as they "hate the gnome". Read more »

[Update - 11:40am CST on May 18] With the day upon us, we've announced the winners.

[Update - 12:15pm CST on May 11] Submissions for the art contest are now closed, but you still have until 11:59pm EST / 10:59pm on May 17, 2010 to leave a comment below for a chance to randomly win some other Left 4 Dead swag. Read more »

On Monday, Valve began polling Left 4 Dead 2 gamers if they would like to see the recent multiplayer mutation "Realism Versus" become a permanent gameplay mode.

The results are in and nearly 500,000 voting gamers have ruled in favor of Realism Versus becoming a regular multiplayer mode in L4D2! Democracy rocks! Read more »

The new weekly mutations for Left 4 Dead 2 are changing up the game in some creative ways. Through this framework, Valve can push live weekly gametypes that do not require additional assets to play, but change up the game in significant ways.

This week, players can try out "Bleed Out": Read more »

Never one to follow convention, Team Fortress 2 developer Valve Software is celebrating the class-based shooter's 119th update with a grand bonanza that will reward players with gold, siver or bronze in-game medals according to their veterancy.

'Grizzled Veterans' who began playing within the first three months after release will receive the top medal, followed by 'Soldiers of Fortune' who started within three months to a year after release, while 'Weekend Warriors' who began after then will receive bronze medals. Valve has yet to reveal when exactly players will be decorated. Read more »

The Mac OS version of Valve's digital distribution platform Steam will be released on May 12, the company confirmed today.

No other details on the launch were given--the announcement was a brief two sentences--though it will presumably debut alongside the native Mac versions of Left 4 Dead, Left 4 Dead 2, Team Fortress 2, Counter-Strike, Portal and the Half-Life series originally slated to launch with the Mac client in April 2010. Read more »

With Left 4 Dead 2's downloadable content 'The Passing' out on Xbox 360 and hitting PC later today, Valve has released a trailer as well as a few more 'Mutation' details.

The Mutations are week-long events that offer new ways to play the game, such as this week's "Realism Versus" Mutation and the upcoming campaign-only "Chainsaw Massacre," which will give players chainsaws with unlimited gas--and nothing else. Read more »

[Update - 2:00pm CST] Valve has now confirmed that "The Passing" will hit both Xbox 360 and PC on Thursday, April 22. As expected, the Xbox 360 download will be priced at 560 Microsoft Points / $7, while those playing on PC will get it for free.

The company also provided details on "Mutations," described as "a series of weekly game mode events" that " range from 'Realism Versus' mode to 'Chainsaw Massacre,' which gives all players chainsaws with an unlimited supply of gasoline." Read more »

Left 4 Dead 2 developer Valve Software has revealed the achievements due to be added to the zombie apocalypse shooter by its upcoming downloadable content 'The Passing,' which neatly teases some of the multiple new game modes that it'll deliver.

One achievement involves "Cache Grab," which Valve describes as involving new foot lockers, while another is awarded for playing 6 mysterious "Mutations." Valve offers no explantation of what Mutations are, instead promising to reveal them tomorrow. Read more »